It looks like the ceasefire is off. After nearly seven months of standing down,  Shiite hardline fighters from Moqtada al-Sadr's Mahdi Army clashed with Iraqi security forces in Basra today. The reaction in Baghdad was almost immediate: the Green Zone was pounded with mortars or rockets throughout the day and at least one office of the rival Badr organization was torched. Clashes were also reported in Kut and a handful of smaller cities in the Shia-dominated south. By sundown, a curfew was in place in Basra, Kut, Hilla, Diwaniya and Sadr City to keep the violence from spreading.

The fighting comes as little surprise. For months, there has been a tense standoff in Basra between the Mahdi fighters loyal to cleric al-Sadr, the Islamic Supreme Council in Iraq (ISCI) and the Fadhila party, an offshoot of the Sadrists. They have carefully carved out their turf: the Mahdi fighters have infiltrated the police force, the ISCI  Shiites control a handful of posts on the local governorate council and the Fadhila party holds the Basra governor post and dominates the security forces which protect the oil fields, Iraq's largest. There are nearly half a dozen smaller militant Shia groups, like Jundallah, who also claim influence in the city. In the past year, the tension between these groups has repeatedly spilled over to street violence. And, after British forces withdrew from their base within Basra last December, it was inevitable that the militias would clash with the Iraqi security forces who replaced them. The latest reports indicate that today's fighting has left at least 15 people dead and dozens more wounded.